Colored hydrocarbons



, 13910-521" (civilian aviation gasonne I 925,333 7 COLORED HYDROCARBONS Kodak comp n Rochester, N .Y., a corporation f of 'Nevr Jersey I I 1 a No Drawing. Application May 24,1955

Serial lio. 10,855 I H 9 (Cl. M -59) This invention relates to the art of coloring hydro .carbons such as petroleum distillates. I It is particularly directedto the coloring of'gasoline.

i Gasolines, whether used for automobile engi g engines or aviation engine's,;for example,- are u'sually dy'ed adistinctiv'e color such asyello'w, orange, bron egred,

blue; green andpur le. Colorationgis employed, for example, to identify .the'yarious grades ofga ialtion d in gasoline, to distinguish manufacturerbrands n H somecases to makeadulterationor misuse difiicult. Eoi' some applications there are specifications whichiie'gulate :IohuW. Thompson, Kingsport, Tenn, assignor to East'- I yum ,...Rignied Feb Lfi mfio .inthe intake system'ofthe engine. Additionally, the

coloring material should have adequate solubilityin gasoa material or dye should:

the composition and concentration f.of the dye or dyesused to color the ga'soline. At thepreserit time these specifications include .Mil-F-S 572 (militaryaviation line), MilG-305 6 (military motor gasoline), and" ASTM Fur her, w. the

tailoring "of gasoline that contains. tetrathyl 'lead.' Oilucts such as furnace oil's;lubricatingoils,jfn1ineral oils, greases, waxes and syntheticlub'rica'nts' Surgeon General, Us. Public Health service, equires the v soluble dyes are alsov frequentlyus'ed to color otherpi'od- I vInasmuch as the most unpo'rta t use of the invention I is-ine nnection with the coloring of. gasoline the invention will be "described primarily with reference to the coloration ofgasoliiie. n v w In coloring engine fuels such as gasoline it is very line, should color the gasoline a satisfactory color and the colored gasoline should have satisfactory. stability upon exposure 'to lightand upon storage. v

- To be satisfactory for use 'in gasoline the coloring 1) Have high 'ti'nctorial value. w n (2) Be solublein gasoline tQ-fthe extent required *for commercial use. p r H v (3) Have adequate solubility intetr'aethyl lead mixes ifintended for coloring such fluids.

, (4) Color gaso1ine to specified hues depending upon 'theapplic'ation. v V,

('5) Contain little or no material that is insoluble'in gasoline.

(6) Be in a compact, noncaking, nondusting form. ('1) Have adequate color fastne ss in gasoline during H storage oron'fexposure to light.

' {(8) Leave "a inimum deposit in the motor induction (9) jBe eornpatible with other additives and should not fafiec't the other properties of the fuel adversely;

"1(1 0)"B'e nonex't'ractible from gasoline by wate chugtic, or acid solutions.

' ('11) Meet the Surgeon Generals 'requi f6;-

leaded gasoline color.

The current gasoline dyes are hydrocarbon-soluble, organic compounds, usually 'of'th'egaio or anthraquinone type. Probably the four most commonly used are the yellow, orange, red and blue dyes prescribed and ASTM specifications for gasoline. These fou'r dyes are:

rn'BLE I Specification Shade ialuet'tnrtjn.m ms amyiami-noy.

anthraquinone. n, a.

Dye Color Name M Strliehii'e Yellow 1 l,l I-l3in:ethyl-p-plieuyl- Aviation gasolinagreeii;

. tazo'aniline. Motor-gasolme'red.

- a l, l-lfhenyl' a zo-g'naphthoh-Li Aviation gasoline brown.

. i R8a.....'. Mbjtnil] derivatives of, Aviationg asolinered, blue, "(4-pheu'ylazophenyl brown, purple; Motor s f azol-Z-naphthol. :1 I Y .gasohne red.

, .Ay iationi'gasolinered,blue,

green, brown, purple. I

such as gasoline. These compounds are especially distinguished by their remarkable tinctorial power. As

specifically shown hereinafter their tinctorial power for I gasoline is. more than three (in most cases more than four) times as great as that of N,N-dimethyl-p-phenylazoaniline, the dye most Widely used to color gasoline yellow today. N-sec-butyl-p-(4-nitrophenylazo)aniline appears to be particularly advantageous and especial claim is made to this compound as a new compound and to its use for coloring hydrocarbons. The exceptional utility of the compounds of the present invention as dyes for gasoline, for example, could not have been predicted. By blending the yellow dyes of the present invention with other suitable dyes for gasoline colors, other than yellow, can be obtained. a

In addition to having remarkable tinctorial power for gasoline the four azo compounds named in the preceding paragraph are otherwise satisfactory as dyes for gasoline. Thus, because of their great tinctorial power for gasoline and their relatively low cost of manufacture their use to color gasoline is considerably more economical than the standard yellow dye N,N-dimethyl-p-phenylazoaniline currently in large use. The savings in dyeing costs is apparent from the fact that only about one third to about one fourth as much dye is required as formerly. Further, because of the much smaller amount of dye required, there is much less danger of excessive amounts of dye depositing in the engine.

The azo dye compounds of the invention are prepared by coupling diazotized p-nitroaniline with N-secondarybutyl aniline, N-isobutyl aniline, N-n-butyl aniline and N-ethyl-o-toluidine, respectively. Advantageously the coupling reaction is carriedout in the presence of a nonionio wetting agent and a large volume of water employing a slow crystallization technique. By carrying out the coupling reaction in the manner just indicated thedyes are obtained in an easily handled crystalline form rather than as a gummy material. When the dyes were prepared ,by carrying out the coupling reaction in a small volume and recovering the product formed by drowning in water, gummy products were obtained.

Nonionic wetting agents that can be employed include, for example, the alkylarylpolyether alcohols made by condensing alkylphenols with ethylene oxide in various proportions. Typical proportions range from six to fourteen parts of ethylene oxide by weight to one part alkyl phenol. Suitable alkylarylpolyether alcohol wetting agents include those sold under the trade names Triton X-102, Triton X-l55, Sulfanole NO-9 and Tergitol NPX. Of the wetting agents used in preparing the azo dye compounds of the invention Triton X-102 is preferred.

TIN CT ORIAL STRENGTH AND HUE MATCH Gasoline solutions of test and standard dyes were compared in a Duboscq colorimeter. Stock solutions of the dyes in benzene were prepared to contain 2.64 mg. of

dye/cc. These stock solutions were pipetted into watercalculated from the dial readings at matched color as follows:

Tinctorial strength, percent dial reading for std. dye filial reading for test dye Thus, a tinctorial strength" of 200% indicates that the experimental dye has twice thecolorin'g power of the standarddye.

' The reliability of this procedure using the colorimet' er was checked by visual comparison of S-ounce andVzgallon samples of gasoline containing 10 mg. of standard dye per gallon and the tinctorial equivalent of the test dye. Reasonably good correlation was observed.

In the description which follows the preparation of the azo compounds of the invention and their use for coloring hydrocarbons, particularly gasoline, is described.

" Example 1 13.8 parts of p-nitroaniline were added to a mixture of 19.3 parts of sulfuric acid and 87 parts of water. The resulting mixture was warmed to complete solution of the p-nitroaniline' and .then poured, with stirring, into a mixture of 170 parts of ice'and 10 parts of water. Then a solution of 7.1 parts of sodium nitrite in 15 parts of water were added immediately all at once. The reaction mixture thus obtained was stirred at 0 C.5 C. for about 30 minutes to efiect complete diazotization of the p-nitroaniline. f The diazonium solution thus obtained was added slowly, with stirring, to a mixture of 14.9 parts of N-secondarybutyl aniline in 2 parts of an alkylarylpolyether alcohol and 2400 parts of water. [The coupling reaction which takes place was carried out with stirring at a temperature of about 10 C.15 C. until the reaction product crystallized (6 to 18 hours). The reaction mixture was then neutralized by the addition of 23 parts of sodium bicarbonate and stirred for 30 minutes longer. The precipitated dye compound was recovered by filtration and the dye recovered on the filter was washed with. water until the washings were 'salt free. The dye compound thus obtained was dried at 40 C.- 50 C. 29.7 parts of the brown dye N-sec-butyl-p#(4- nitrophenylazo)aniline having the formula:

/H .l M N. N OH.

CHaCHg were thus obtained. Upon recrystallization from isopropyl alcohol it melts at C.-103 C.

Example 2 By the use of14.9 parts of N-isobutyl aniline in place of N-secondarybutyl aniline in Example 1 a 56% yield of crude N-isobutyl-p-(4-nitrophenylazo)aniline is obtained, which, after recrystallization from methanol, had a melting point of 77 C.-84 C.

Example 3 By the use of 14.9 parts of N-n-butyl aniline in place of N-secondarybutyl aniline in Example 1 a good yield of N-n-butyl-p-(4-nitrophenylazo) aniline is obtained. A portion of this crude product recrystallized from ethanol had a melting point of 156 C.-158 C.

Example 4 By the use of 13.5 parts of N-ethyl-o-toluidine in place of N-secondarybutyl aniline in Example 1 a 46% yield of N-ethyl-p-(4-nitrophenylazo) -o-toluidine having the formula:

I matchi azoaniline.

. is obtained. This-product had (ax-120 c. 1

' Examplej'f i-iTw dye s l ion were prepa ed .zin wat rqwhit straight-run; gasoline so as-to contain 1.54; mg. 9f "N-.s,ec-

ut'y -p-t i-n t p eu .1. 'zolanil ne of ;N,N-dimethyl-P:ph nyla an i per gall n- ?l';he wo .m lti gqmimg rn s DETERMINATION per-gal on udit) the solutions thus prepared looked"identi calin one gallon quanities lay :yisua'l' observation under laboratory light. The, resultslshowed that1N-sec1butyl-p- (4 nitrophenylazo aniline is-an excellent yellow dyefor gasoline 'havjpgsa tinctorial strength of 4551%.;.and gocdihu match: I

v Example'fi g I The colorimeter method described;hereinbeforeQunder the heading Tinctorial Strength and -I'Iue"M-atch was I used to compare N-n-butyl-p (4-nitrophenylazoaniline;with

the standard yellow gasoline dye N,Ndimethyl-p-phenyl azoanilin'e. The results showed thatN n-butyl-peM-nitrmphenylazo) aniline is an excellentyellow dyefor'gasoline having atinctorial strength of-47 6% -?a good hue' Example 7 The colorimeter -rn'ethod described-under Tinctorial Strength and line Match was used to comparethe dye N-. e,thyl-p- 4 -nitrophenylazo -o-t'oluidi and yellow'gasoline dye N,N-dirne'thyl The. results showed that toluidine is a ver'ygood yllowydyfe forggasoline having'a tinc'torial strength of'345%"and" xcellent huefnjatchu Example 8' f if .The colorimeter method descrihedfaboveiunder the heading Tinctorial Strength and Hue Match was used to compare N -iso'butyl'-p-(4-nitrophenylazo)aniline withthe standard yellow gasoline dye N,N-d-iinethyl-p pheiiylaxo aniline. The results showed that having a tinctorial strength of 400% and a good hue match. I V

I Example 9 v a This example shows that the-azo compounds of the invention are useful dyes for jet engine fuels and distillate burner fuels. Samples of a typical water-white straight-run jet fuel JP-3 grade) were dyed with 10 -rng./gal. of the" standard yellowdye NJi-dirnethyl-p-v phenylazoaniline and 2.2 mg./ gal. .of the dye N-sec-butylp-(4-nitrophenylazo)aniline, respectively. ;200 cc. sam ples of these dyed fuels looked identical when observed N-iso'butyl-p-(4- nitro- I phenylazo)anilin e is an excellent yellow dye for gasoline wi h the s andhenylaz'oah-ilinm yl-P:(4:1:i p ni/Iam) pletely'settled. Then'SOcc. portions of the supernatant liquid were pipetted into ..Weighed;beakers of the. type ilscd for the gasoline gum test. The gasoline was evapoe rated in an ASTM gum unit .at,.210 '.F.' -under ,en-ailj flow, of 0,5 liter/second. After coolingand weighing .the residue, and subtractinga blank-fr) the undyed (gasoline, the maximum solubility of the" dyewas calculated as 'amsPer gal1on.----

TABLE its-COMPARISON wmi *STANDXRD YELLOW; GAS.0LINE DYE v I Tinctorial azo(auiline. N tl-methylhexyl) p (4-nitroazo)an lne aniline. N-ethyl-p- (4- nitrophenylazo)- uldlne.

Excellent... -.o-tol 1 Solubility of yellow std.=35.4 gJgal.

The results set forth in Table 11 show that it could not have been predicted that. I

' N-sec-butyl-p-(4-nitrophenylazo) aniline,

N-isobutyl-p-(4-nitrophenylazo) aniline, N-mbutyl-p- (4-nitrophenylazo) aniline and N-ethyl-p-(4-nitrophenylazo) -o-toluidine would be outstanding yellow dyes for gasoline. No explanationfor the poor tinctorial value ofN-tert-butyl-pin eight-ounce oil sample bottles under laboratory light. I

Example 10 a N-n-butyl-p-(4-nitrophenylazo)aniline and the standard yellow dye N,N-dimethyl-p-phenylazoaniline were compared as dyes for the synthetic colorless lubricating oildi-(Z-ethylhexyl) sebacate. The tests showed that 4.4 mg. of N-n-butyl-p-(4-nitrophenylazo)aniline colored the synthetic lubricating oil equally as well as 20mg. of the yellow standard dye. obtained. v v.

Other alkaline agents such as sodium carbonate, disodium phosphate, potassium acetate and .A fairly good color rna potassium carbonatecan be used in place of sodium bicarbonate in Example 1.

acetate, fsodium ch was Table ll given hereinafter sets-forth the results fol.

tain'ed when variousazo compounds were compared with the standard yellow gasoline dye N,N dimethyl-p-phenyl- The table sets. forth the 'tinctorial strength, the hue match and the maximum solubility in jgrams .npergallon of the dyes compared with the standard yellows bline y proper dosage. dyes'would be dissolvedin gasoline'is well known to '(4-nitrophenylazo)aniline' and .N-n-pentyl-p (4-nitrophenylazo) aniline is known.

It is here" noted that the azocompounds of the present invention in addition to having outstanding tinctorial power for gasoline meet the other requirements of a satis-;

factory gasoline dye such, as oil solubility, distinctive shade, color fastness, and compatibility with other additives'such as tetraethyl lead fluid, antioxidants and metal de'activators. The properties of a satisfactory gasoline dye have been set forth more fully hereinbefore and the azo. compounds of the invention satisfactorily meet the properties previously, set forth.

No particular techniques are required to get the azo dyes of the present invention dissolved in gasoline. They are handled and added to gasoline by the same processes now used-for other powdered gasoline dyes. Perhaps the most common method now in use is the dry dye 1 eductor system wherein powdered dye is sucked directly from the shipping container into the gasoline being dyed using. standard equipment'and controls to insure Inasmuch as the manner in which the those skilled in the art to which this invention is directed,

y no further discussion on this point is believed necessary.

' I claim:

l. A petroleum distillate colored with a dye compound selected from the dye compounds consisting of dissolved therein, said dye compound being present in the proportion of about 1.50 mg. to about 100 mg. per gallon of said gasoline.

3. A gasoline containing tetraethyl lead colored with a dye compound selected from the dye compounds consisting of N-sec-butyl-p- 4-nitrophenylazo) aniline, N-isobutyl-p-(4-nitrophenylazo)aniline, N-n-butyl-p-(4-nitrophenylazo)aniline and N-ethyl-p-(4-nitrophenylazo)-o-toluidine dissolved therein, said dye compound being present in the proportion of about 1.50 mg. to about 100 mg. per gallon of said gasoline.

4. A petroleum distillate colored with N-sec-butyl-p- (4-nitrophenylazo) aniline dissolved therein, said N-secbutyl-p-(4-nitrophenylazo) aniline being present in the proportion of about 1.50 mg. to about 100 mg. per gallon of said petroleum distillate.

5. A gasoline colored with N-sec-butyl-p-(4-nitro- 8. phenylazolaniline dissolved therein, sa'id N-sec-but'yl-p (4-nitrophenylazo)aniline being present in the proportion of about 1.50 mg. to about mg. per gallon of said gasoline.

6. A gasoline containing tetraethyl lead colored with N-sec-butyl-p-(4 nitrophenylazo) aniline dissolved therein, said N-sec-butyl-p-(4-nitrophenylazo)aniline being present in the proportion of about 1.50 mg. to about 100 mg. per gallon of said gasoline.

7. A gasoline colored with N-isobutyl-p-(4-nitrophenylazo)aniline dissolved therein, said N-isobutyl-p- (4-nitrophenylazo)aniline being present in the proportion of about 1.50 mg. to about 100 mg. per gallon of said gasoline.

8. A gasoline colored with N-n-butyl-p-(4-nitrophenylazo) aniline dissolved therein, said N-n-butyl-p-(lnitrophenylazo)aniline being present in the proportion of about 1.50 mg. to about 100 mg. per gallon of said gasoline.

9. A gasoline colored with N-ethyl-p-(4-nitrophenylazo)-o-toluidine dissolved. therein, .said N-ethyl-p-(4- nitrophenylazo)-o-toluidine being present in the proportion of about 1.50 mg to about 100 mg. per gallon of said gasoline.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Textile Colorist, Acetate Rayon by Synfil," December 1943, pages 551-553. 

1. A PETROLEUM DISTILLATE COLORED WITH A DYE COMPOUND SELECTED FROM THE DYE COMPOUNDS CONSISTING OF N-SEC-BUTYL-P-(4-NITROPHENYLAZO) ANILINE, N-ISOBUTYL-P-(4NITROPHENYLAZO) ANILINE, N-N-BUTYL-P-(4-NITROPHENYLAZO) ANILINE AND N-ETHYL-P-(4-NITROPHENYLAZO(-O-TOLUIDINE DISSOLVED THEREIN, SAID DYE COMPOUND BEING PRESENT IN THE PROPORTION OF ABOUT 1.50 MG. TO ABOUT 100 MG. PER GALLON OF SAID PETROLEUM DISTILLATE. 